As an example let us consider the possibility of reconstructing \(f(R)\)  so as to reproduce exactly the same background evolution as produced by the observationally successful \(\Lambda \) CDM model. This reconstruction exercise is in principle possible, but the reconstructed \(f(R)\)  can be written only in terms of Hypergeometric functions [1]}, [2]}. \(\Lambda \) CDM cosmology can be specified by the simple cosmographic requirement [3]}, [4]}
\(j=K+1\,.\) 
